Superficial, Cutaneous and Subcutaneous Mycoses Flashcards
what are the three cutaneous mycoses?
dermatophytosis, tinea versicolor and tinea nigra
how prevalent is dermatophytosis? what fungus causes it?
it is very common caused by three different genera of fungi- epidermophyton, trichophyton and microsporum
what does dermatophytosis infect? what are the symptums called?
infect superficial keratinized structures.
symptoms are called tinea
what three known syndromes are caused by dermatophytosis?
jock itch, athlete’s foot and ringworm
how is dermatophytosis transmitted?
by fomites or autoinnoculation
how is dermatophytosis diagnosed?
by KOH mount, culture, PPD or woods lamp exam
how is dermatophytosis treated?
treat all affected body sites simultaneously wiht topical antifungal cream or treat with oral griseofulvin
how does tinea versicolor appear? what is it caused by?
hypo or hyperpigmented areas on the trunk, back or abdomen. caused by overgrowth of normal flora Malassezia
how is tinea versicolor diagnosed? treated?
KOH mount of skin scrapings
treat with selenium sulfide cream or oral azoles
how common is tinea nigra? what is it caused by?
uncommon
infection of injured extremity by soil organism werneckii
what does tinea nigra look like? what can it be confused with?
is a dark brown spot that may be confused with melanoma
how is tinea nigra diagnosed?
by KOH mount for thick septate branching hyphae with dark pigment in walls. can also culture on sabouraud’s agar at room temperature for shiny black colonies
how is tinea nigra treated?
with tipical salicylic acid and topical azole
what are the three subcutaneous mycoses?
sporotrichosis, chromomycosis and mycetoma
what is sporotrichosis caused by? what is its morphology?
sporothrix spp. thermally dimorphic fungi
how is sporotrichosis transmitted?
enters the skin through small injuries (thorns and splinters) from vegetation
what are the symptoms of sporotrichosis?
painless ulcer at the site of puncture spreads up the lymphatic over the years
when is sporotrichosis pulmonary?
when there is COPD
what may happen with sporotrichosis infection in immunosuppressed patients?
disseminated or meningial infection
how is sporotrichosis diagnosed?
by biopsy with round or cigar shaped yeast
if cultured at room temp from pus there will be hyphae and conidia
how is sporotrichosis treated?
oral azoles. more serious forms may need to be treated with Amphotericin B
what is another name for chromomycosis? what is it caused by?
chromoblastomycosis
caused by injuries to the feet that are infected by a variety of tropical soil fungi
what does chromomycosis look like?
looks like gradually spreading wartlike or plaque lesions with scattered black dots
how is chromomycosis diagnosed?
KOH mount shows gray or black septate hyphae or conidia. if the dark spots are biopsied, there would be round fungal cells inside leukocytes or giant cells
how is chromomycosis treated?
with a combination of flucytosine, itraconazole, local surgery and heat
how prevalent is mycetoma? where does it infect and what organism is it caused by?
rare infection of wounds on extremeties
petriellidium or madurella from the soil cause it
what does mycetoma look like?
forms abscesses, granulomas and pus with granules
how is mycetoma diagnosed? treated?
with biopsy
treat with combination of surgery, IV amphotericin B and oral azole
what does candida look like? what is the most common?
multimorphic- yeastlike, pseudohyphal and hyphal forms
most common is c albicans- normal flora
what are the most common presentations of candidiasis?
thrush (inhalers/AIDS), vaginitis and diaper rash.
what are less common presentations of candidiasis? what are they associated with?
hand infections (dishwashers), folliculitis, chronic mucocutaneous (with genetic cell mediated immunity deficiency) and full GI infections associated with leukemia
when are candidemia and disseminated disease a concern?
with patients with cell mediated immune deficiency
how is candidiasis diagnosed?
by exam, biopsy, culture and/or CT
how is candidiasis treated?
treatment ramps up with severity of disease. topical azoles for superficial, graduating to oral azoles and then adding amphotericin b for life threatening infections
what is a major concern with candidal infections, especially in the hospital setting?
drug resistance. should evaluate in culture before administering antifungals
